This application relates generally to acoustic probes. More specifically, this application relates to apparatus and methods for testing acoustic probes.
Acoustic imaging techniques are valuable in a wide range of applications. While the most notable are undoubtedly medical applications in the form of ultrasound imaging, acoustic techniques are more generally used at a variety of different acoustic frequencies for imaging a variety of different phenomena. For example, acoustic imaging techniques may be used for the identification of structural defects and for detection of impurities, in addition to taking advantage of the nonionizing character of ultrasound radiation for imaging living biological bodies. Just some of the medical applications for acoustic imaging include the imaging of fetuses being carried by pregnant women, the detection of tumors in various organs of the body, particularly in soft-tissue structures, and the imaging of organs when real-time information is the preferred method for diagnostic functions with echocardiography.
All of these techniques rely fundamentally on the fact that different structures, whether they be biological or otherwise, have different acoustic impedances. When acoustic radiation is incident on an acoustic interface, such as where the acoustic impedance changes discontinuously because of the presence of a tumor in an organ, it may be scattered in ways that permit characterization of the interface. Radiation reflected by the interface is most commonly detected in such applications, but there are certain ultrasound scanning methodologies that additionally or alternatively make use of transmitted radiation.
Transmission of the acoustic radiation towards a target and receipt of the scattered radiation may be performed and/or coordinated with a modern acoustic imaging system. Many modern systems are based on multiple-element array transducers that may have linear, curved-linear, phased-array, or similar characteristics. These transducers may, for example, form part of an acoustic probe coupled with the acoustic system to perform the actual acoustic measurements. In some instances, the imaging systems are equipped with internal self-diagnostic capabilities that allow limited verification of system operation, but do not generally provide effective diagnosis of the transmission and receiving transducer elements that make up the probe itself. Degradation in performance of these elements is often subtle and occurs as a result of extended transducer use and/or through user abuse. Acoustic imaging systems therefore often lack any direct quantitative method for evaluating probe performance.
There is accordingly a general need in the art for apparatus and methods for testing acoustic probes.